Power transmission belt and apparatus for and method of making same

ABSTRACT

A power transmission belt and an apparatus for and method of making such a belt are provided wherein the belt is adapted to be moved in an endless path and has a load-carrying section which is made of a plastic-like material having elongated particles made of a reinforcing material embedded therein and each of the particles has a longitudinal axis which is arranged substantially in alignment with the endless path.

United States Patent Fisher [1 1 3,657,938 1 1 Apr. 25, 1972 [54] POWERTRANSMISSION BELT AND APPARATUS FOR AND METHOD OF MAKING SAME [72]Inventor: David G. Fisher, Springfield, Mo. [73] Assignee: DaycoCorporation, Dayton, Ohio [22] Filed: Nov. 9, 1970 [21] Appl.No.: 88,040

52 us. (:1 ..74/233, 74/234, 156/140 51 1 1111.01 ..Fl6g 5/16, 82% 7/221581 Field ofSearch ..74/233, 234, 231 156/140,

[56] References Cited UNITED STATES PATENTS 2,677,969 5/1954 Waugh..74/233 3,523,462 8/1970 Beindorf ..74/233 3,584,516 6/1971 Burpulis..74/233 FOREIGN PATENTS OR APPLICATIONS 512,941 8/1952 Belgium..l56/l39 Primary ExaminerLeonard I-I. Gerin AltorneyReuben Wolk [5 7]ABSTRACT A power transmission belt and an apparatus for and method ofmaking such a belt are provided wherein the belt is adapted to be movedin an endless path and has a load-carrying section which is made of aplastic-like material having elongated particles made of a reinforcingmaterial embedded therein and each of the particles has a longitudinalaxis which is arranged substantially in alignment with the endless path.

16 Claims, 6 Drawing Figures PATENTEDAPRZS r912 3. 657, 938

I i FIG-6 mvewrok DAVID G. FISHER IFIG'5 BY m mm,

A TTOR/VE Y POWER TRANSMISSION BELT AND APPARATUS FOR AND METHOD OFMAKING SAME BACKGROUND OF THE INVENTION Endless power transmission beltssuch as flat belts, V-belts, toothed belts, and the like, are often madeusing various types of elastomeric materials and may be made usinginjection molding techniques. In producing each of these belts considerable attention is given to providing a load-carrying section ineach belt which is of optimum strength and minimum cost; nevertheless,the load-carrying sections of present belts either require the use ofcomparatively expensive materials or must be made using time consumingtechniques in order to assure that their associated belts provide therequired performance.

SUMMARY This invention provides an improved endless power transmissionbelt of simple and economical construction and an improved apparatus andmethod for making such a belt. In particular, the belt of this inventionhas a load-carrying section which is made of a plastic-like materialhaving elongated members or fibers made of a reinforcing materialembedded therein and each of the members or fibers has a longitudinalaxis which is arranged substantially in alignment with the endless pathof the belt. I

Other details, uses, and advantages of this invention will be readilyapparent from the exemplary embodiment thereof presented in thefollowing specification, claims and drawing.

BRIEF DESCRIPTION OF THE DRAWING The accompanying drawing shows anexemplary embodi ment of this invention, in which FIG. 1 is afragmentary perspective view of a power transmission belt of thisinvention;

FIG. 2 is an enlarged fragmentary cross-sectional view taken essentiallyon the line 2-2 of FIG. 1;

FIG. .3 is a fragmentary perspective view of an assembly having atension section and a load carrying section provided as a part thereofwith such assembly being disposed within a cavity of an injectionmolding apparatus to enable injecting an elastomeric material withinsuch cavity and against the loadcarrying section to define a compressionsection and the completed belt of FIG. 1;

FIG. 4 is a view similar to FIG. 3 after injecting the elastomericmaterial in position to define the compression section;

FIG. 5 is a schematic elevational view with parts in cross section andparts broken away illustrating an apparatus which may be used to definean endless load-carrying member for the exemplary belt of FIG. 1; andFIG. 6 is an enlarged cross-sectional view with parts broken away takenessentially on the line 6-6 of FIG. 5.

DESCRIPTION OF ILLUSTRATED EMBODIMENT Reference is now made to FIG. I ofthe drawing which illustrates an exemplary embodiment of a powertransmission belt of this invention in the form of a belt popularlyreferred to as a V-belt which is designated generally by the referencenumeral 10. The belt 10 is made utilizing an apparatus or mold 11illustrated in FIGS. 3 and 4.

The belt 10 comprises an outer fabric cover 12, a tension section 13, acompression section 14, and a load-carrying section arranged between thetension section and the compression section. The load-carrying sectionis made separately as an endless member or band and has elongatedmembers or fibers 16 of a reinforcing material embedded therein, seeFIG. 2.

The tension section 13 is made of a material having high resiliency andthe fabric cover 12 and tension section 13 are bonded together as aunitusing any technique known in the art and the load-carrying section ormember 15 is suitably bonded in position against the tension section todefine an assembly 18. The assembly 18 is disposed within a cavity 17 ofthe mold l1 and the compression section 14 injection molded thereagainstin a manner to be described in detail subsequently to define thecompleted belt 10.

The member 15 may be bonded against the tension section 13 usingsuitable bonding means prior to insertion of the assembly 18 within themold cavity 17 or the unit comprised of cover 12 and tension section 13may be placed in the cavity 17 and the load-carrying member 15 bonded inposition in the mold 11. This bonding may also be achievedsimultaneously with the injection of the compression section 14 in thecavity 17 and the bonding of such compression section against member 15.

The mold 11 is comprised of a plurality of cooperating rings comprisinga bottom ring 21, a central ring 22, and a top ring 23, which aresuitably held together. The top ring 23 has a plurality of verticalpassages 24 extending vertically therethrough and the passages 24 may besupplied with elastomeric material using any techniques known in theart. For example, the passages 24 may be supplied by a plurality ofradially extending passages (not shown) which may be supplied'by acentral sprue, or the like.

The central ring 22 has a stepped surface 25 of roughly L- shapedcross-sectional outline formed therein and once the top ring 23 issuitably held in position in the assembled mold 11 the surface 25cooperates with an oppositely arranged bot tom surface 26 of the topring 23 to define an annular passage 27 of rectangular cross-sectionaloutline which leads directly into the mold cavity 17. Thus, once theassembly 18 is installed in the mold 11 elastomeric material flowsthrough the passages 24 into the annular passage 27 and into the moldcavity 17 to define the compression section 14 of the transmission belt10. The belt 10 is then cured and cooled using conventional techniquesand removed from the mold 11.

The load-carrying member 15 is preferably made of a comparativelyinexpensive plastic-like material which has the rein forcing fibers 16,see FIGS. 24, embedded therein. The member 15 is made by injectionmolding techniques using a mold 30 as shown in FIG. 5.

A flowable plastic-like material 31 with particles or fibers l6dispersed therein is provided under pressure to the mold 30 using aconduit 32 which is in flow communication with a suitable source of suchplastic-like material. The conduit 32 has a circular cross-sectionalconfiguration and the elongated reinforcing fibers are randomlydispersed in the material without any particular orientation asillustrated at 33 in FIG. 5

The conduit 32 introduces the material 31 into a dwell chamber 34 in themold 30 and such chamber communicates with one end 35 of a gate 36 inthe mold 30. The opposite end 37 of the gate 36 communicates with anannular chamber 40 in the mold 30. The annular chamber 40 is defined bya plurality of cooperating surfaces in the mold 30 and such surfacesdefine chamber 40 having a trapezoidal cross-sectional configuration,see FIG. 6.

The gate 36 has what may be described as a flattened substantially ovalconfiguration and has a height indicated at 41 in FIG. 6 which is quitesmall compared to the length 42 and width 43 of such opening, which areshown in FIGS. 5 and 6 respectively. The height 41 may be generally ofthe order of several thousandths of an inch and the configuration of thegate 36 assures that the reinforcing fibers 16 have their longitudinalaxes aligned parallel to the opposed parallel walls or surfaces definingthe height 41 of the gate 36.

The gate 36 may be in the form of a fan gate and is arranged so that itsdischarge end 37 is tangent to the annular chamber 40 in the mold 30. Asthe fiowable plastic-like material 31 is injected into the chamber 34the gate 36 aligns the reinforcing fibers 16 so that they flowsubstantially normal to a vertical plane through the outlet end of thegate 36. Thus, as the fibers or elongated-members 16 flow into theannular chamber 40 their axes are substantially in alignment with theendless path defined by chamber 40.

. made of fiber glass.

The material 31 with its oriented or aligned fibers 16 is then curedusing any suitable technique known in the art to define the completedmember'lS. The aligned fibers have high tensile strength along theirlongitudinal axes and they serve to substantially increase the strengthof the load-carrying member 15 while allowing such load-carrying sectionto be made of flexible comparatively inexpensive plastic-like materials.Further, by making the member 15 using injection molding techniques, itis possible to produce such member in an automated production line atminimum cost.

The annular chamber 40 of the mold 30 may have any desiredcross-sectional configuration such as rectangular, trapezoidal, etc., tothereby define member 15 having a corresponding cross-sectionalconfiguration. Further, the loadcarrying member 15 may be dimensioned sothat it extends across the full width 'of its belt (as in this example)or may be smaller than the full width. In this latter instance, smallwidths of the elastomeric material used to define the compressionsection 14 would also be bonded in position against opposite side edgesof the member 15.

Any suitable plastic-like material and associated reinforcing fibers maybe used to define the load-carrying section or member 15. For example,member 15 may be made of nylon which has its fibers 16 provided in theform of fiber glass.

The belt 10 is shown as a V-belt having a standard roughly trapezoidalcross-sectional configuration. However, it will be appreciated that thisinvention may be employed to define belts having any desiredconfiguration. Further, the tension and compression sections 13 and 14respectively are preferably made of suitable natural or synthetic rubbercompounds.

The height 41 of the gate 36 used to inject elastomeric material intothe mold chamber 40 has been described as being generally of the orderof several thousandths of an inch, 7

and a height of 0.005 inch is considered acceptable for particles orfibers made of fiber glass. However, it will be appreciated that suchheight will be determined by the cross-sectional thickness of the fibersl6 and the properties of its associated plastic-like material 31.

The fibers or elongated particles 16 are'comparatively short as comparedto the overall length of the belt. For example, such fibers may beafractional part of an inch in length, i.e., roughly one-half of an inchin length.

While present exemplary embodiments of this invention, and methods ofpracticing the same, have been illustrated and described, it will berecognized that this invention may be otherwise variously embodied andpracticed within the scope of the following claims.

What is claimed is: 1. A power transmission belt adapted to be moved inan endless path, said belt comprising a tension section, a compressionsection, and a load-carrying section bonded against adjoining surfacesof said tension and compression sections, said load-carrying sectionbeing made of a plastic-like material and having elongated reinforcingparticles embedded therein with each of said particles having alongitudinal axis which is arranged substantially in alignment with saidendless path.

2. A belt as set forth in claim 1 in which said load-carrying section ismade as a separate member and has one surface bonded against saidtension section and said compression section is injection molded against'a surface of said load-carring section which is arranged opposite fromsaid one surface.

3. A'belt as set forth in claim 1 in which said load-carrying sectionextends across the full width of said belt.

4. A belt as set forth in claim 1 in which said tension and compressionsections are made of rubber, said load-carrying section is made ofnylon, and said particles comprise particles 5. A method of making anendless power transmission belt comprising the steps of, providing aload-carrying member which is made of a plastic-like material and isadapted to be moved in an endless path, said member having reinforcingfibers embedded therein with their longitudinal axes arrangedsubstantially parallel to said endless path, bonding said member to aconstruction which comprises a tension section in said belt to define anassembly, disposing said assembly in an annular cavity of an associatedmold apparatus, and injection molding an elastomeric material againstsaid member to define a compression section for said belt.

6. A method as set forth in claim 5 in which said bonding step comprisesplacing said construction in said cavity and bonding said member againstsaid construction.

7. A method as set forth in claim 5 in which said providing stepcomprises flowing a flowable plastic-like material having reinforcingfibers randomly dispersed therein through a gate into an annular chamberof another mold causing the longitudinal axes of said fibers to bearranged substantially in alignment with an endless path defined by saidchamber, and curing said flowable material to define said load-carryingmember.

8.'An injection molding apparatus for making a load-carrying member fora power transmission belt, said apparatus comprising, cooperatingsurfaces defining an annular chamber which is adapted to receive aflowable plastic-like material having reinforcing fibers dispersedtherein, and a gate in said apparatus having a discharge end which isarranged tangent to said annular chamber, said gate causing thelongitudinal axes of said fibers to be arranged substantially inalignment with an endless path defined by said chamber upon flowing saidflowable plastic-like material and fibers therethrough.

'9. An apparatus as set forth in claim 8 in which said gate has a heightgenerally of the order of several thousandths of an inch and saiddischarge end extends across practically the full width of said annularchamber.

10. An apparatus as set forth in claim 8 in which said cooperatingsurfaces define a chamber having a trapezoidal cross-sectional outlinewhereby said load-carrying member is provided for a V-belt.

. 11. An apparatus as set forth in claim 8 and further comprising adwell chamber provided in saidapparatus, said dwell chamber being inflow communication with one end of said gate, and a conduit forsupplying said flowable plastic-like material under pressure to saiddwell chamber. 7

12. An apparatus as set forth in claim 8 in which said gate has a heightgenerally of the order of several thousandths of an inch and saiddischarge end extends across practically the full width of said annularchamber, and said apparatus further comprising a dwell chamber providedtherein, said dwell chamber being in flow communication with one end ofsaid gate, and a conduit for supplying said flowable plastic-likematerial under pressure to said dwell chamber.

13. A method of making a load-carrying member for a power transmissionbelt, said method comprising'the steps of, flowing a flowableplastic-like material having reinforcing fibers randomly dispersedtherein through a gate into an annular chamber of a mold causing thelongitudinal axes of said fibers to be arranged substantially inalignment with an endless path defined by said chamber. and curing saidflowable material to define said load-carrying member having saidreinforcing fibers aligned with the endless path of said member.

14. A method as set forth in claim 13 in which said flowing stepcomprises flowing a flowable nylon having reinforcing fibers of fiberglass randomly dispersed therein.

15. A method as set forth in claim 13 in which said flowing stepcomprises flowing said plastic-like material under pressure firstthrough a dwell chamber which communicates with said gate and thenthrough said gate.

16. A method as set forth in claim 13 in which said flowing stepcomprises flowing a flowable nylon having fibers of fiber glassdispersed therein and said flowing step further comprises flowing saidnylon and its dispersed fibers through a gate having a height generallyof the order of 0.005 inch and a width at

1. A power transmission belt adapted to be moved in an endless path,said belt comprising a tension section, a compression section, and aload-carrying section bonded against adjoining surfaces of said tensionand compression sections, said loadcarrying section being made of aplastic-like material and having elongated reinforcing particlesembedded therein with each of said particles having a longitudinal axiswhich is arranged substantially in alignment with said endless path. 2.A belt as set forth in claim 1 in which said load-carrying section ismade as a separate membEr and has one surface bonded against saidtension section and said compression section is injection molded againsta surface of said load-carring section which is arranged opposite fromsaid one surface.
 3. A belt as set forth in claim 1 in which saidload-carrying section extends across the full width of said belt.
 4. Abelt as set forth in claim 1 in which said tension and compressionsections are made of rubber, said load-carrying section is made ofnylon, and said particles comprise particles made of fiber glass.
 5. Amethod of making an endless power transmission belt comprising the stepsof, providing a load-carrying member which is made of a plastic-likematerial and is adapted to be moved in an endless path, said memberhaving reinforcing fibers embedded therein with their longitudinal axesarranged substantially parallel to said endless path, bonding saidmember to a construction which comprises a tension section in said beltto define an assembly, disposing said assembly in an annular cavity ofan associated mold apparatus, and injection molding an elastomericmaterial against said member to define a compression section for saidbelt.
 6. A method as set forth in claim 5 in which said bonding stepcomprises placing said construction in said cavity and bonding saidmember against said construction.
 7. A method as set forth in claim 5 inwhich said providing step comprises flowing a flowable plastic-likematerial having reinforcing fibers randomly dispersed therein through agate into an annular chamber of another mold causing the longitudinalaxes of said fibers to be arranged substantially in alignment with anendless path defined by said chamber, and curing said flowable materialto define said load-carrying member.
 8. An injection molding apparatusfor making a load-carrying member for a power transmission belt, saidapparatus comprising, cooperating surfaces defining an annular chamberwhich is adapted to receive a flowable plastic-like material havingreinforcing fibers dispersed therein, and a gate in said apparatushaving a discharge end which is arranged tangent to said annularchamber, said gate causing the longitudinal axes of said fibers to bearranged substantially in alignment with an endless path defined by saidchamber upon flowing said flowable plastic-like material and fiberstherethrough.
 9. An apparatus as set forth in claim 8 in which said gatehas a height generally of the order of several thousandths of an inchand said discharge end extends across practically the full width of saidannular chamber.
 10. An apparatus as set forth in claim 8 in which saidcooperating surfaces define a chamber having a trapezoidalcross-sectional outline whereby said load-carrying member is providedfor a V-belt.
 11. An apparatus as set forth in claim 8 and furthercomprising a dwell chamber provided in said apparatus, said dwellchamber being in flow communication with one end of said gate, and aconduit for supplying said flowable plastic-like material under pressureto said dwell chamber.
 12. An apparatus as set forth in claim 8 in whichsaid gate has a height generally of the order of several thousandths ofan inch and said discharge end extends across practically the full widthof said annular chamber, and said apparatus further comprising a dwellchamber provided therein, said dwell chamber being in flow communicationwith one end of said gate, and a conduit for supplying said flowableplastic-like material under pressure to said dwell chamber.
 13. A methodof making a load-carrying member for a power transmission belt, saidmethod comprising the steps of, flowing a flowable plastic-like materialhaving reinforcing fibers randomly dispersed therein through a gate intoan annular chamber of a mold causing the longitudinal axes of saidfibers to be arranged substantially in alignment with an endless pathdefined by said chamber, and curing said flowable material to definesaid load-carrying member having said reinforcing fibers aligNed withthe endless path of said member.
 14. A method as set forth in claim 13in which said flowing step comprises flowing a flowable nylon havingreinforcing fibers of fiber glass randomly dispersed therein.
 15. Amethod as set forth in claim 13 in which said flowing step comprisesflowing said plastic-like material under pressure first through a dwellchamber which communicates with said gate and then through said gate.16. A method as set forth in claim 13 in which said flowing stepcomprises flowing a flowable nylon having fibers of fiber glassdispersed therein and said flowing step further comprises flowing saidnylon and its dispersed fibers through a gate having a height generallyof the order of 0.005 inch and a width at its discharge end whichextends across practically the full width of said annular chamber.